The Hypersonic Air-breathing Weapon Concept is an unmanned hypersonic cruise missile launched during a flying mission by a B52H bomber.
In March, a B-52 Stratofortress off the West Coast dropped the Hypersonic Air-breathing Weapon Concept. According to DARPA, it reportedly reached elevations of more than 65,000 feet and travelled more than 300 nautical miles. The Pentagon delayed announcing the test for two weeks to avoid escalating already-tense relations with Russia. CNN was the first to report on the test’s details and why it was not immediately revealed.
Hypersonic weapons have a maximum speed of five times that of sound and are very agile. They are more challenging to track and destroy than traditional ballistic missiles due to their ability to reverse direction mid-flight.
Source: https://www.defensenews.com/air/2022/04/05/pentagon-kept-hypersonic-test-quiet-amid-russia-tensions/